: Attention-deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed pediatric behavioral disorder. Primary care physicians, especially pediatricians, have historically played a large role in the diagnosis and treatment of ADHD. Despite the existence of authoritative guidelines to assist primary care physicians, ample evidence demonstrates that they continue to diagnose and treat this disorder sub optimally. This is due, in part, to a lack of training and cumbersome delivery system designs. Modern computer decision support strategies offer the best hope of equipping general practitioners to deal with ADHD. We have developed a novel decision support system for implementing clinical guidelines in pediatric practice. CHICA (Child Health Improvement through Computer Automation) combines three elements: (1) pediatric guidelines encoded in Arden Syntax;(2) a dynamic, scan able paper user interface;and (3) an HL7-compliant interface to existing electronic medical record systems. The result is a system that both delivers "just-in-time" patient-relevant guidelines to physicians during encounters, and accurately captures structured data from all who interact with it. Preliminary work with CHICA has demonstrated the feasibility of using the system to implement and evaluate clinical guidelines. We propose to expand CHICA to include ADHD treatment and diagnosis modules. The specific research aims of this proposal are to (1) expand and modify an existing computer based decision support system (CHICA) to include ADHD treatment and diagnosis guideline rules as well as the capability to fax data directly into the medical record, and (2) evaluate the effect of the CHICA system on the processes of ADHD care in pediatric practices, including adherence to guidelines for ADHD treatment and diagnosis. This study will include a randomized trial to compare the change in quality of ADHD patient care in intervention and control practices. To measure the effect of the CHICA system on the process of ADHD related patient care (aim 2), we will collect data from medical records and surveys of nurses and providers. Additionally, information about practice characteristics will be collected at baseline. We will assess the quality of ADHD services at baseline and again at 12 months post implementation. These methods will allow a thorough description of the intervention's role in the process of ADHD management.